1. Field of the Invention
The present invention relates to a regenerator for use in a Stirling refrigerator, i.e. a refrigerator based on the principle of the Stirling cycle, for the purpose of accumulating the heat of working gas.
2. Description of the Prior Art
FIGS. 1 and 2 show a conventional regenerator designed for use in a Stirling cycle based system. This regenerator 1 is produced by forming irregularities on the surface of a resin film 2 by bonding a plurality of extra-fine spacers 4 at regular intervals and parallel to one another, and then winding the resin film 2 up into a cylindrical shape.
FIG. 3 shows an example of a Stirling refrigerator of a free piston type provided with a regenerator 1 as described just above. This Stirling refrigerator has a cylinder 8 filled with working gas such as helium, a piston 5 and a displacer 7 for dividing the space inside the cylinder 8 into a compression space 9 and an expansion space 10, a linear motor 6 for driving the reciprocating movement of the piston 5, plate springs 11 and 12 for supporting the piston 5 and the displacer 7 in such a way as to permit, by resilience, their reciprocating movement, a heat absorber 14 provided at the expansion space 10 so as to absorb heat from the outside, and a heat dissipater 13 provided at the compression space 9 so as to dissipate heat to the outside.
Reference numeral 15 represents a heat exchanger for heat dissipation, and reference numeral 16 represents a heat exchanger for heat absorption. These heat exchangers serve to prompt the exchange of heat between the inside and the outside, and the regenerator 1 is arranged between these exchangers.
In this Stirling refrigerator having the structure described above, when the linear motor 6 is driven, the piston 5 moves upward inside the cylinder 8, compressing the working gas inside the compression space 9. During this time, although the temperature of the working gas rises, the heat is dissipated through the heat-dissipation heat exchanger 15 and then through the heat dissipater 13 to the outside air, and thus the working gas is cooled, achieving isothermal compression. The working gas compressed inside the compression space 9 is, by its own pressure, transferred through the regenerator 1 into the expansion space 10. During this time, the heat of the working gas is accumulated in the resin film 2 constituting the regenerator 1, causing the temperature of the working gas to fall.
A predetermined phase difference is kept between the reciprocating movement of the displacer 7 and that of the piston 5. When the displacer 7 moves downward, the working gas inside the expansion space 10 expands. During this time, although the temperature of the working gas falls, heat is absorbed from the outside air through the heat absorber 14 and then through the heat-absorption heat exchanger 16, and thus the working gas is heated, achieving isothermal expansion. A while later, when the displacer 7 starts moving upward, the working gas inside the expansion space 10 is transferred through the regenerator 1 back to the compression space 9. During this time, the heat that has previously been accumulated in the regenerator 1 is transferred to the working gas, causing the temperature of the working gas to rise. This sequence of events, called the Stirling cycle, is repeated by the reciprocating movement of the piston 5 and the displacer 7, and, as a result, heat is steadily absorbed through the heat absorber 14 and transferred to the working gas, gradually cooling the absorber 14.
In this way, in the Stirling refrigerator, by transferring the working gas back and forth between the compression space 9 and the expansion space 10 through the regenerator 1, heat is absorbed from the outside air so as to achieve the cooling of the absorber 14. Meanwhile, the regenerator 1 accumulates heat from the working gas in its compressed, and thus hot, state, and transfers the heat back to the working gas in its expanded, and thus cold, state. Here, the larger the amount of heat so accumulated, the higher the heat exchange efficiency, and thus the higher the cooling performance of the Stirling refrigerator.
However, the above-described conventional regenerator 1 for use in a Stirling cycle based system is very expensive because it requires undue time and labor for its production, which involves the bonding, one by one, of the spacers 4 on the surface of the resin film 2. Moreover, as shown in FIG. 4, the working gas passing through the gaps between different turns of the resin film 2, as it passes from the edge of the regenerator 1 inward, tends to move away from the surfaces of the resin film 2 and concentrate roughly at the center of the gaps, because boundary layers develop (in the figure, arrows 20 indicate the flow of the working gas). This lowers the heat transfer rate between the working gas and the resin film 2.
An object of the present invention is to provide an inexpensive regenerator for use in a Stirling cycle based system by simplifying the production process thereof.
Another object of the present invention is to achieve satisfactorily high heat accumulation performance.
To achieve the above objects, according to one aspect of the present invention, a regenerator for use in a Stirling cycle based system, such as is arranged between a compression space and an expansion space of the Stirling cycle based system so as to serve as a flow passage for working gas transferred back and forth between the compression space and the expansion space and simultaneously serve to accumulate the heat of the working gas, is produced by forming a plurality of ribs integrally on a surface of a resin film and winding the resin film up into a cylindrical shape.
According to another aspect of the present invention, a regenerator for use in a Stirling cycle based system, such as is arranged between a compression space and an expansion space of the Stirling cycle based system so as to serve as a flow for working gas transferred back and forth between the compression space and the expansion space and simultaneously serve to accumulate the heat of the working gas, is produced by joining together two or more cores in the direction of the axes of the cores. Here, the cores are each produced by forming a plurality of ribs integrally on a surface of a resin film and winding the resin film up into a cylindrical shape.
According to still another aspect of the present invention, a regenerator for use in a Stirling cycle based system, such as is arranged between a compression space and an expansion space of the Stirling cycle based system so as to serve as a flow passage for working gas transferred back and forth between the compression space and the expansion space and simultaneously serve to accumulate the heat of the working gas, is produced by forming a plurality of ribs integrally on both surfaces of a resin film and winding the resin film up into a cylindrical shape. Here, the ribs are inclined relative to the axis of the regenerator.